The present invention relates to a sealed container for containing therein a liquid such as lactic acid beverage, milk, or powder or others.
Various types of container structures have been developed for containing lactic acid beverage, milk, juice, oil or others. Many efforts are made to prevent leakage through a region where an end closure member is sealed to a container body. One such effort is that a bottom open end of the container body is closed by an end closure member by depressing the end closure member into the bottom open end of the container body with a peripheral portion of the end closure member engaged by the marginal edge of the container body, as disclosed in my copending U.S. application, Ser. No. 678,107, entitled "LIQUID CONTAINER SEALING CONSTRUCTION AND METHOD AND APPARATUS FOR PRODUCING THE SAME", filed Apr. 19, 1976, now abandoned.
With regard to the top end of the container, the top enclosure is sealed to the body after the liquid or other material is poured into the container. This differs from the sealing of the bottom end of the container body and makes it difficult to seal completely the container body with the enclosure.
In case of "cover-bonding" type of containers, a top enclosure or cover is bonded to the edge of the container body. For such a reason, the edge of the body is usually so thick that the cover can be easily bonded to the thick edge thereof without any deforming of the top end of the container body. However, it is difficult to produce the "cover-bonding" type of container bodies made of paper material because the thick edges of the container bodies can not easily be formed. This is a reason why most of known containers of such a type are made of plastic materials.